Compression behavior of delaminated composite plates
The response of delaminated composite plates to compressive inplane loads was investigated. The delaminated region may be either circular or elliptical, and may be located between any two plies of the laminate. For elliptical delaminations, the axes of the ellipse may be arbitrarily oriented with respect to the applied loads. A model was developed that describes the stresses, strains, and deformation of the sublaminate created by the delamination. The mathematical model is based on a two dimensional nonlinear plate theory that includes the effects of transverse shear deformation. The model takes into account thermal and moisture induced strains, transverse pressures acting on the sublaminate, and contact between the sublaminate and plate. The solution technique used is the Ritz method. A computationally efficient computer implementation of the model was developed. The code can be used to predict the nonlinear load-strain behavior of the sublaminate including the buckling load, postbuckling behavior, and the onset of delamination growth. The accuracy of the code was evaluated by comparing the model results to benchmark analytical solutions. A series of experiments was conducted on Fiberite T300/976 graphite/epoxy laminates bonded to an aluminum honeycomb core forming a sandwich panel. Either circles or ellipses made from Teflon film were embedded in the laminates, simulating the presence of a delamination. Each specimen was loaded in compression and the strain history of the sublaminate was recorded far into the postbuckling regime. The extent of delamination growth was evaluated by C-scan examination of each specimen. The experimental data were compared to code predictions. The code was found to describe the data with reasonable accuracy.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 5962022
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
ALUMINIUM
CARBON
COMPARATIVE EVALUATIONS
COMPOSITE MATERIALS
COMPRESSIBILITY
COMPUTER CODES
DEFORMATION
ELEMENTAL MINERALS
ELEMENTS
EPOXIDES
FAILURES
GRAPHITE
HONEYCOMB STRUCTURES
LAYERS
MATERIALS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MECHANICAL STRUCTURES
METALS
MINERALS
NONLINEAR PROBLEMS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PLATES
RITZ METHOD
STRAINS
STRESSES